Guessing, even wrongly, is thought toactivate webs of knowledge, which leadsto richer encoding of the correct answer.

It’s well known that taking tests helps us learn. The act of retrieving information from memory helps that information stick. This seems intuitive. More surprising is the recent discovery that guessing aids subsequent learning of the correct answer, even if your initial guess was wrong.

Let’s consider a simple example in the context of learning capital cities. Imagine you don’t know the capital of Brazil. In the first scenario, I show you the word Brazil and your task is to say the capital. Because you don’t know, you guess “Rio de Janeiro”. This guessing phase takes 8 seconds. I then show you, for 5 seconds, the word Brazil together with the correct answer “Brasilia”. In the second scenario, you simply have 13 seconds to study the country/capital pairing Brazil and Brasilia.

Later on, I test you on the capital of Brazil. The new research on guessing finds that you’re more likely to recall the correct answer in the first scenario, in which you initially guessed wrong. This is counter-intuitive for two reasons – first, you had less time to study the correct information (5 seconds vs. 13 seconds), and second, you came up with a wrong answer, which you’d think would interfere with your memory for the correct answer once I gave it to you.

How can this be? A new study by Veronica Yan and her colleagues at the University of California, Los Angeles, puts two possibilities to the test. To understand the first of these, we need to realise that prior research on the guessing effect has tended to use word pairs related by meaning, such as “olive” and “branch” or “whale” and “mammal”. Some participants simply study the word pairs, others guess each partner word before being shown the correct word. The guessing process leads to superior memory for the word pairs than simply studying them, even when the guessing is wrong.

Crucially, this past research has tended to use word pairs only weakly related in meaning, while the participants in the guessing condition usually guess strongly related words. Yan and her colleagues reasoned that this could be a way for the guessing process to be a memory aid. When it comes to the memory test on the word pairs, participants in the guessing condition can use the rule of the thumb “the correct answer is always weakly related to the first word”. This is a shrewd observation on the part of Yan and her team, but they found no evidence support their theory. The beneficial guessing effect still occurred even when they used a mix of strongly and weakly related word pairs.

The second explanation Yan’s team tested had to do with whether a person’s guesses are always wrong. If the initial guess is always wrong, perhaps this makes it easy to always suppress the guess information, thereby aiding recall of the correct answer once it’s given. Yan’s team also found this explanation wanting. Participants still benefited from the guessing effect even when the procedure was rigged so that half their guesses were right and half were wrong.

Yan et al’s final study examined the duration of the beneficial guessing effect. They reasoned that perhaps the benefit will only be short-lived, while participants are easily able to remember and suppress their guessed answer. In fact the learning benefits of guessing, even incorrectly, was found even when participants were tested 61 hours after the guessing process.

So why does guessing have this beneficial effect for learning? The truth is we still don’t really know. An explanation with growing support has to do with what psychologists call “semantic activation”. Essentially they’re saying that guessing activates the mental web of knowledge and facts associated with the correct answer, which makes the subsequent storage of that correct information easier once it’s given. “The basic idea is that this [guessing-related] activation … affords a richer encoding of the subsequently presented target,” the researchers said.

From a practical perspective, this research on the beneficial effects of guessing suggests that teachers shouldn’t worry too much about giving students tests that are too difficult. Even if they keep getting the answers wrong, so long as they’re given the correct information afterwards, the act of guessing is actually likely to assist their learning, not hinder it.